With the increasing proportion of new energy in energy system

the automatic generation control(AGC) frequency modulation technology for the combination of thermal power unit and energy storage system is developing rapidly in China's power industry. Combined with compensation rules of auxiliary frequency modulation in southern market

this study explains the calculation method and significance of AGC performance index in power plant

and introduces the characteristics of assisting thermal power units with AGC. From the perspective of improving the AGC frequency modulation performance of the unit

the energy storage charging and discharging control strategy is formulated

and the influence of energy storage power and energy storage capacity on the comprehensive frequency regulation performance of AGC is studied

through the simulation of joint frequency regulation with the original AGC. An electricity market model and a profit evaluation model are established. On this basis

recommendations for configuration of energy storage capacity is given. The simulation results show that

a reasonable configuration of the energy storage system can significantly improve the frequency modulation performance of conventional units and bring obvious frequency modulation benefits.